'\" te
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.TH PICLD 8 "May 16, 2020"
.SH NAME
picld \- PICL daemon
.SH SYNOPSIS
.nf
\fB/usr/lib/picl/picld\fR
.fi

.SH DESCRIPTION
The Platform Information and Control Library (\fBPICL\fR) provides a mechanism
to publish platform-specific information for clients to access in a
platform-independent way. \fBpicld\fR maintains and controls access to the
\fBPICL\fR information from clients and plug-in modules. The daemon is started
in both single-user and multi-user boot mode.
.sp
.LP
Upon startup, the \fBPICL\fR daemon loads and initializes the plug-in modules.
These modules use the \fBlibpicltree\fR(3PICLTREE) interface to create nodes
and properties in the \fBPICL\fR tree to publish platform configuration
information. After the plug-in modules are initialized, the daemon opens the
\fBPICL\fR daemon door to service client requests to access information in the
\fBPICL\fR tree.
.SS "PICL Tree"
The \fBPICL\fR tree is the repository of all the nodes and properties created
by the plug-in modules to represent the platform configuration. Every node in
the \fBPICL\fR tree is an instance of a well-defined \fBPICL\fR class. The name
of the base \fBPICL\fR class is \fBpicl\fR, which defines a basic set of
properties that all nodes in the tree must possess. Two of those properties are
\fBname\fR and \fB_class\fR, where \fBname\fR contains the name of the node,
and the \fB_class\fR contains the \fBPICL\fR class name of the node. Certain
nodes in the \fBPICL\fR tree have well-known names. For example, the name of
the root node of the \fBPICL\fR tree is \fB/\fR and the name of the root node
of the sub-tree containing platform device nodes is \fBplatform\fR.
.SS "PICL plug-in Modules"
The \fBPICL\fR plug-in modules are shared objects that publish
platform-specific data in the \fBPICL\fR tree. They are located in well-known
directories so that the daemon can locate and load them.
.sp
.LP
Plug-in modules are located in one of the following plug-in directories
depending on the platform-specific nature of the data that they collect and
publish:
.sp
.in +2
.nf
/usr/platform/`uname -i`/lib/picl/plugins
/usr/platform/`uname -m`/lib/picl/plugins
.fi
.in -2
.sp

.sp
.LP
A plug-in module can specify its dependency on another plug-in module using the
\fB-l\fR or \fB-R\fR linker option. The plug-ins are loaded by the daemon using
\fBdlopen\fR(3C) according to the specified dependencies. Each plug-in module
must define a \fB\&.init\fR section, which is executed when the plug-in module
is loaded, to register themselves with the daemon. See
\fBpicld_plugin_register\fR(3PICLTREE) for additional information on plug-in
registration.
.sp
.LP
The plug-in modules use the \fBlibpicltree\fR(3PICLTREE) interface to publish
nodes and properties in the \fBPICL\fR tree so that clients can access them.
.sp
.LP
When the \fBPICL\fR daemon invokes the initialization routine of the plug-in
module, the plug-in collects the platform information and creates nodes and/or
properties to represent the configuration in the \fBPICL\fR tree. A plug-in can
create additional threads to monitor the platform configuration and update the
\fBPICL\fR tree with any changes. This enables a \fBPICL\fR plug-in to operate
as a daemon within the \fBPICL\fR framework.
.sp
.LP
An environmental monitor is an example of a plug-in module that uses a thread
to monitor the temperatures and fan speeds of the platform, then publishes the
environmental information in the \fBPICL\fR tree so clients can access them.
.sp
.LP
Clients use the \fBlibpicl\fR(3PICL) interface to send requests to \fBpicld\fR
for accessing the \fBPICL\fR tree.
.SH EXIT STATUS
\fBpicld\fR does not return an exit status.
.SH FILES
.ne 2
.na
\fB\fB/var/run/picld_door\fR\fR
.ad
.RS 23n
\fBPICL\fR daemon door
.RE

.sp
.ne 2
.na
\fB\fB/usr/lib/picl/picld\fR\fR
.ad
.RS 23n
\fBPICL\fR daemon
.RE

.SH SEE ALSO
.BR svcs (1),
.BR dlopen (3C),
.BR libpicl (3PICL),
.BR libpicltree (3PICLTREE),
.BR picld_log (3PICLTREE),
.BR picld_plugin_register (3PICLTREE),
.BR attributes (7),
.BR smf (7),
.BR svcadm (8)
.SH NOTES
The \fBpicld\fR service is managed by the service management facility,
\fBsmf\fR(7), under the service identifier:
.sp
.in +2
.nf
svc:/system/picl
.fi
.in -2
.sp

.sp
.LP
Administrative actions on this service, such as enabling, disabling, or
requesting restart, can be performed using \fBsvcadm\fR(8). The service's
status can be queried using the \fBsvcs\fR(1) command.
